Surge depressor



Dec. 4, 1962 Filed Aug. 16, 1960 J. H ROTHENBERG ETAL 3,066,701

suRGE DEPREssoR 2 Sheets-Sheet 1 JEROME H. ROTHENBERG- ELLIGTT F. WRIGHT IN V EN TORS Dec. 4, 1962 Filed Aug. 16, 1960 J. H. ROTHENBERG ETAL SURGE DEPRESSOR 2 Sheets-Sheet 2 JEROME H. ROTHENBERG ELLIOTT F. WRIGHT INVENTORS United States Patent Office Patented Dec. 4, 1962 3,066,701 SURGE DEPRESSOR Jerome H. Rothenberg, Colonia, and Elliott F. Wright,

Plainfield, NJ., assignors to Worthington Corporation,

Harrison, NJ., a corporation of Delaware Filed Aug. 16, 1%0, Ser. No. 50,011 Claims. (Cl. 13S- 30) This invention relates to surge depression for noncompressible fluid systems. More particularly it is an improved surge chamber.

Surges or shock waves moving at acoustic velocity in non-compressible fluid systems may be detrimental and may be superimposed upon each other amplifying the peak pressure. Thus the effectiveness with which these surges are attenuated has a direct bearing upon the initial cost and life of the system.

Accordingly this invention is a surge depressor with improved cost and performance characteristics. More particularly this invention contemplates a casing defining a surge chamber for inclusion in a non-compressible fluid system. Gas in the chamber forms a pocket against which the liquid is cushioned. Energizing means are provided to control the volume yof the gas pocket. The energizing means are disposed externally of the casing and are operable in response to changes in the volume of the gas pocket.

Basically this surge depressor offers a rugged inexpensive completely automatic design with improved performance and maintenance features. Intermittent operation of a heater as the energizing means permits the use of constant power output heaters. Wrap around heaters do not interfere with the structural integrity of the casing and they also insure the electrical isolation of the heater from the chamber. Control of heater operation is responsive to variations of thermal signals making use of the heaters as the thermal signal emitters and the casing as the signal transmission medium.

These and other advantages will be seen more fully from the specification and claims viewed in conjunction with the accompanying drawing of a preferred embodiment of the surge depressor in which:

FIGURE 1 is a fragmented elevation view.

FIGURE 2 is a plan view.

FIGURE 3 is a schematic representation of the surge depressor and associated controls.

In the drawing casing 11 defines vertical closed ended surge chamber 12 with lower end 13 and upper end 14. Lower end 13 may be arranged to -accommodate the inclusion of the surge depressor into any relatively noncompressible fluid system subject to surges. The embodiment shown in the drawing is especially suited for installation in a hydraulic system downstream of a reciprocating pump to reduce the effect of pulsations.

The operation of this surge depressor is best seen from FIGURE 3. Gas in the surge chamber 12 provides a gas pocket 16 in communication with the fluid system against which surges transmitted by the fluid are cushioned. Energizing means generally described 17 control the volume of gas pocket 16. The energizing means 17 could employ any of the known techniques for increasing the energy of a gas. In the shown embodiment, heaters 18 are employed to boil or flash the pumped liquid 19 thereby increasing the supply of gas. Upper 21 and lower 22 electrical wrap around tubular type heaters with substantially constant heat output and other desirable characteristics serve as heaters 18. Thus, in the shown hydraulic system, boiled water develops a pocket of steam in chamber 12. The steam pocket 16 provides an energy balance by compressing at peak pressures and expanding at low pressures thereby picking energy up from and discharging energy to the hydraulic system.

' casing 11.

In this manner the amplitudes of surges of the hydraulic system are depressed.

Heaters 21 and 22 operate intermittently to generate steam. Heater actuating means generally described 23 are provided to regulate the operation of the heaters. Control of heater actuating means 23 is accomplished by sensing Variations in thermal signals using upper 24 and lower 26 thermocouples disposed on the outside 27 of casing 11.

Variations in the thermal signals result from changes in the volume of gas pocket 16 which is manifested by movement of liquid surface 28. As will be seen below, except for a brief start-up period, upper heater 21 will generally not be in use, so when lower heater 22 is on, it will be emitting a constant heat signal. The specific heat of water and steam are markedly different and their respective film coefficients will be correspondingly different. The film coeicient may be here thought of as a measure of the rate of heat flow from lower heater 22 through casing 11 to the hydraulic system. As the surge chamber heats up liquid surface 28 drops and steam replaces water in contact with interior 29 of wall 31 and the temperature of wall 31 will increase because of the lesser ability of steam than water to remove heat from The higher temperature of wall 31 will be sensed by lower thermocouple 26 which will cause lower thermocouple switch 32 to cut out power to lower heater 22.

As surge chamber 12 cools the steam volume decreases, liquid surface 23 rises and consequently the thermal signal from lower heater 22 to lower thermocouple 26 is diminished causing lower thermocouple switch 32 to close activating lower heater 22. Thus, the volume of gas pocket 16 will be automatically adjusted when the surge depressor is in normal operation. Gas volume control will be fully accomplished ordinarily by lower thermocouple 26 associated with lower heater '22. Upper thermocouple switch 33 is provided to actuate upper heater 21 by virtue of a low thermal signal at start-up.

By the arrangement shown in the drawing, upper thermocouple 24 will always be subjected to a high thermal signal when chamber 12 has gas pocket 16 developed therein. Accordingly, after an initial start-up period, upper heater 21 will remain olf. In this regard, upper thermocouple 24 and upper heater 21 provide extra power at start-up to lessen the time requirement for the surge depressor to come to full cushion.

Top end 34 of casing 11 defines exhaust port 36 communicating with gas pocket 16 whereby gas may be expelled from surge chamber 12. Also in the event of nonfunction or malfunction of the heaters, exhaust port 36 provides means for introducing a leak to lessen peak stresses.

Reflector shield 37 and insulation 38 embracing casing 11 and heaters 21, 22 minimizes heat loss.

It will be understood that changes may be made in the details of construction and in the correlation of the various elements of this surge depressor to accomplish the same results without departing from the scope of the invention defined in the claims.

What is claimed is:

1. A surge depressor in a substantially non-compressible fluid system comprising, a casing having a closed upper end and an open lower end connected to said fluid system, chamber means formed in said casing and having an upper gas portion and a lower fluid portion therein, the upper gas portion of said chamber means having gas therein produced by boiling the fluid of said system, at least one heater mounter externally about said casing and having a substantially constant heat output, said heater including a coil member disposed about said casing, at least one thermocouple externally connected to said cassnee,

ing, actuating means for said heater connected operatively responsive to pre-set temperatures of said therniocouple, a heater switch operatively associated with said heater and controlled by said Vactuating means whereby the temperature of said thermocouple will operate said actuating means to either open or close said heater switch to operate or shut down said heater.

2. The combination claimed in claim 1 wherein said coil member having an internal diameter substantially equal to the external diameter of said casing, said coil member mounted about said casing in engagement therewith and adapted to be removed from the closed end of said casing.

3. The combination claimed in claim 2 wherein said heater contained within a reflector shield, insulation disposed outwardly of said shield to reduce heat losses.

4. A surge depressor in a substantially non-compressible fluid system comprising, a casing having a closed upper end and an open lower end to connect to said fluid system, chamber means formed in said casing and having an upper gas portion and a lower fluid portion therein, the upper gas portion of said chamber means having gas therein produced by boiling the fluid of said system, an upper heater and a lower heater externally mounted about said casing and each of said heaters having a substantially constant heat output, said upper heater and said lower heater each including a coil member disposed about said casing, an upper switch to operate said upper 4 heater and a lower switch to operate said lower heater, an upper thermocouple and a lower thermocouple eX- ternally connected to said casing, upper actuating means operative responsive to said upper thermocouple to control said upper heater switch during the startup operation of said surge depressor whereby said upper heater causes the fluid to boil sooner thereby forming the gas for said gas portion of said chamber means faster, lower actuating means operatively responsive to pre-set temperatures of said lower thermocouple to control said lower heater switch during normal Operation of said surge depressor whereby gas is maintained in the gas portion of said chamber means.

5. The combination claimed in claim 4 wherein: (a) said upper heater disposed above and adjacent to said lower heater, (b) said upper thermocouple disposed above said upper heater, (c) said lower thermocouple disposed below said lower heater.

References Cited in the file of this patent UNlTED STATES PATENTS 1,893,847 Simpson Jan. 10, 1933 2,839,594 Schneidersmann June 17, 1958 2,949,932 Hewitt Aug. 23, 1960 2,963,044 Hellund Dec, 6, 1960 

